The present invention relates to liquid injection into containers and particularly to a container inspection system for sampling and determining the presence of certain substances, such as residues of contaminants of ammonium salts and amine salts within containers such as glass or plastic bottles. More specifically, the present invention relates to an improved sampling and analyzing system and method for determining the presence of residues of these contaminants in containers such as beverage bottles rapidly moving along a conveyor past a test station in a container sorting system.
In many industries, including the beverage industry, products are packaged in containers which are returned after use, washed and refilled. Typically refillable containers, such as beverage bottles, are made of glass which can be easily cleaned. These containers are washed and then inspected for the presence of foreign matter.
Glass containers have the disadvantage of being fragile and, in larger volumes, of being relatively heavy. Accordingly, it is highly desirable to use plastic containers because they are less fragile and lighter than glass containers of the same volume. However, plastic materials tend to absorb a variety of compounds which may later be desorbed into the product thereby potentially adversely affecting the quality of the product packed in the container. Examples of such compounds are ammonium salts, amine salts, ammonia, organic nitrogen compounds, and hydrocarbons including gasoline and various cleaning fluids.